Solve the equation A =1/2 bh for h

Evaluate 4 a for a = 5 2/3 . express your answer in simplest form.

Each month, a shopkeeper spends 5x + 14 dollars on rent and electricity. if he spends 3x−5 dollars on rent, how much does he spend on electricity? for which value(s) of x is the amount the shopkeeper spends on electricity less than $100? explain how you found the value(s).

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?